Lavandula angustifolia Mill. (lavender) and Origanum heracleoticum L. (greek oregano) are aromatic plants used in traditional medicine for relief of convulsion, anxiety, insomnia and in the treatment of neurological disorders. On the basis of literature, we evaluated the changing in glutathione enzymatic activities provoked by the essential oils and pure components, linalool, carvacrol and limonene to study the mechanisms of action, responsible for several activities. Activities of SOD (superoxide dismutase) and GPx (glutathione peroxidase) tend to increase respect to control. SOD maximal increase reached up to 117% for carvacrol and limonene. Increase in GPx activity reached even up to value 1.229 for origanum oil in comparison to control 0.125 μkat/mg prot. Activities of GR (glutathione reductase), except for lavender, showed a biphasic response. Like for GR, the administration of compounds, resulted in a biphasic response in GST (glutathione-S-transferase) activities (with a consistent increase in activity at concentration 125 μg/mL for all compounds except lavender). Moreover, the changes in GSH (reduced glutathione), are no significant for different concentrations of essential oils. So, the biological properties of essential oils and specifically, the antioxidant ones, can be related to their capacity to modify the glutathione enzymatic activities.